Fuel injection system for use in multicylinder compression-ignition engines



s. HINCHCLIFFE 2,317,947

YSTEM FOR USE IN MULTICYLINDER COMPRESSION-IGNITION ENGINES 2 Sheets-Sheet I.

- FUEL INJECTION s Filqd Feb. 13, 1941 Jyolr'zej .Hinglcza ffe Apnl 27; 1943. s. HINCHCLIFFE 2,317,947

FUEL INJECTION SYSTEM FOR USE IN MULTICYLINDER COMPRESSION-IGNITION ENQINES Filed Feb. 13, 1941 2 Sheets-Sheet 2 syczwe qz 'wkczzfre,

Patented Apr. 27, 1943 FUEL INJECTION SYSTEM FOR. USE IN MULTIGYLINDER COMPRESSION- IGNI- TION ENGINES Sydney Hinchclifie, wylasn-on Ty-ne, England ApplicationvF-ebruary 13, 1941, Serial No. 378*,834 In Great Britain Mareh'15, 1294i) 3 Claims. (Cl. 1239-3139) This invention relates to fuel injection systems for use in multi-cylinder compressionignition engines.

The object of the invention is to provide simple and inexpensive means whereby a multicylinder compression-ignition: engine may be made to run in the opposite direction. without the necessity of substantial alterations in; the fuel injection mechanism having to be made or the interposition of special shifting arrangements between the pump plunger and its operating cam, and without any impairment of the efiiciency of the engine when running in the reverse direction, and which at the same time will permit of any timing of the fuel injection, and will be applicable both to two-cycle and four-cycle engines.

It has been proposed to provide a compressionignition. engine in which the crankshaft was rotatable in the opposite direction, and symmetrical cams were used for this purpose, but when the engine was set to turn in the reverse direction the valves were actuated in a reverserelation to thatin which they were actuated. when running in the normal direction, and as a result fuel was injected during the exhaust period and for a considerable period after. It has also been proposed to use a symmetrical fuel pump cam which has its'centre line approximately in line with the engine crank with which it is associated. Obviously however, this principle can only be applied in engines in which the entire injection of fuel occurs before top dead centre. It has further been proposed in the case of four-cycle engines to arrange a symmetrical cam in such a way that the compression stroke top dead centre of a cylinder when running in one direction becomes the exhaust stroke top dead centre when running in the reverse direction. This principle is however limited to four-cycle engines.

According to the present invention, a distributor for delivering fuel oil to the engine cylinders is provided between the fuel pump means and the injectors, and the fuel pump cams are arranged, and said distributor connected between said fuel pump means and the injectors, in such a way that each cam co-acts with a particular engine cylinder when running in one direction but with a different cylinder when running in the opposite direction. With this arrangement any desired timing is obtainable, whether such timing requires entire injection to occur before, or to extend beyond, top dead centre.

: fuel' injectors of the engine on the other hand a distributor for delivering" fuel oil in the requisite'sequence to the engine cylinders.

When running conditions are to be the same in each direction, the angular distance between the two sides of each cam is such that when an engine piston is onthe top dead centre at the beginning of its firing stroke the correct quantity of fuel for that crank position has been delivered, while the cam centre line is angularly distant from the pump centre line by one-half the angular firing interval of theengine.

It will be noticed that in either direction of rotation it is the leading face of each cam which causes injection. Hence when unlike conditions 1 are required for the two directions, the characteristics required for one particular direction can be obtained by shapingand positioning the cam faces which cause injection for that direction of rotation, in accordance with the desired conditions.

It is'not necessary to have the same numberof pump cylinders as'engine cylinders provided there is a fuel delivery for each engine firing stroke.

The invention will now be described by way of example with reference to the accompanying diagrammatic drawings.

In the said drawings:

Fig. 1 is a perspective view showing the firing or injection sequence for a three cylinder twocycle engine, with a one to one pump cam shaft timing.

Fig. 2 is a perspective view showing the firing or injection sequence for a three cylinder twocycle engine as in Fig. 1 but with a one to oneand-a-half pump cam shaft timing.

Fig. 3 is a cross-sectional view of the distributor.

Fig. 4 is a cross-sectional view of the cams of Fig. 2.

Referring more particularly to Fig. 1, A indicates the fuel pump, B its shaft, and C 0 C its axially spaced cams arranged at apart. D indicates the distributor, E the engine, and F the engine crank shaft. The pump A has three cylinders indicated at A A, A which are connected by a common delivery pipe to a central bore in the rotor DR of the distributor which bore communicates with a radial port DR in the said rotor. Equally spaced around the stator are three delivery ports D D, D which communicate respectively with the engine cylinders E E E All three units are shown geared together so that they rotate in the same direction at the same speed. The firing interval is 120.

The operation is as follows: Assume the engine is running anti-clockwise. The pump cylinder A has begun its delivery stroke, and the distributor rotor port DB has uncovered the distributor port D so that oil is being delivered to engine cylinder E When cylinder E has fired, crank F approaches its top dead centre and cam C begins to move the plunger of pump A on its delivery stroke. Meanwhile the distributor rotor port DB has uncovered the distributor port D so that oil is being delivered to engine cylinder E. In the same way in its turn cylinder E has oil delivered to it from pump cylinder A When it is desired to run the engine in the reverse direction, the valve gear having been moved into reverse, starting with the position shown in Fig. 1, the cam C causes the pump cylinder A to deliver oil through distributor port D to engine cylinder E then cam C causes pump cylinder A to deliver oil through distributor port D to engine cylinder E and then cam C causes pump cylinder A to deliver oil through distributor port D to engine cylinder E In the arrangement shown in Fig. 2 the fuel pump G has two cylinders onlyG G with two cams H H arranged at 180 to one another. The other units are identical with those shown in Fig. 1 and are indicated by the same references. The pump cam shaft I is shown as driven at 1 times the speed of the engine shaft. With this arrangement, when the engine is running in a counterclockwise direction pump cylinder G is delivering all to engine cylinder E then pump cylinder 6- delivers through distributor port D to engine cylinder E When the engine is to run in the reverse direction, pump cylinder G2 delivers to engine cylinder E then pump cylinder G delivers through distributor port D to engine cylinder E and then pump cylinder G delivers through distributor port D to engine cylinder E What I claim as my invention and desire to secure by Letters Patent of the United States is:

1. In a fuel injection system for multicylinder compression-ignition engines comprising a plurality of engine cylinders, pistons and injectors in said cylinders, injection pump means, pump cylinders in said injection pump means connected to said injectors, and cams actuating said injection pump means, the construction which comprises a distributor for delivering fuel oil to the injectors, said distributor comprising a stator having a plurality of ports communicating respectively with the injectors, and a rotor inside said stator, said rotor having a port communicating with the delivery side of the fuel pump means, and adapted to communicate in sequence with said stator ports, the cams and rotor port being constructed and timed so that when the cams rotate in a clockwise direction the clockwise face of a particular cam coacts with its pump means and through the distributor with a particular injector While when the cams rotate in the counterclockwise direction the counterclockwise face of another cam coacts with its pump means and through the distributor with the said particular injector.

2. In a fuel injection system according to claim 1, the construction wherein each pump cam is substantially symmetrical, the cams being timed so that one cam is in line with and towards its pump cylinder when the crank shaft is midway between two top dead centers of firing strokes.

3. In a fuel injection system according to claim 1, the construction wherein each pump cam is substantially symmetrical, the cams being timed so that one cam is in line with and towards its pump cylinder when the crank shaft is midway between two consecutive top dead centers of firing strokes, and the angular distance between the two sides of each cam is such that when an engine piston is on the top dead center at the beginning of its firing stroke the correct quantity of fuel oil for that crank position has been delivered, while the cam center line is angularly distant from the pump center line byone-half the angular firing interval of the engine.

SYDNEY I-HNCHCLIFFE. 

